1. Appearance inspection
The quality of the carbon brush can be preliminarily judged through the visual inspection. First of all, check whether the surface of the carbon brush is uniform, whether there are unevenness, bubbles, cracks and other defects. Secondly, it is necessary to check whether the size of the carbon brush meets the requirements, especially whether the length and diameter of the carbon brush are matched with the machine. Finally, check if the color of the carbon brush is consistent, as different colors may cause the density and conductivity of the carbon brush to differ.
2. Hardness testing
Hardness is one of the important indicators to measure the quality of carbon brushes. The higher the hardness, the greater the density, the better the conductivity, and the longer the service life of the carbon brush. We can measure the hardness of carbon brushes with a hardness tester that meets the requirements, usually the hardness of carbon brushes is between 5-8HRA.
3. Conductivity testing
Electrical conductivity is another important indicator, and we can use a multimeter to test the conductivity of carbon brushes. First clamp the carbon brush in the test clip of the multimeter according to the specified method, and then connect the test pen tip to both ends of the carbon brush, if the carbon brush conductivity is good, the value on the multimeter should fluctuate within the normal range, if the value exceeds the normal fluctuation range, it means that the conductivity of the carbon brush is not good.
Fourth, anti-wear detection
Carbon brushes rub a lot during use, so wear resistance is another metric to test. We can use an abrasion tester to test the wear resistance of carbon brushes. During the test, the carbon brushes are placed in the wear tester according to the prescribed method, and then the wear test is carried out. After the test, you can observe the wear and tear of the carbon brush to judge its anti-wear ability.
